Update MainMenu.xib

Author: polina-c

pkgs/example/macos/Runner/Base.lproj/MainMenu.xib

@@ -332,10 +332,10 @@
         </menu>
         <window title="APP_NAME" allowsToolTipsWhenApplicationIsInactive="NO" autorecalculatesKeyViewLoop="NO" releasedWhenClosed="NO" animationBehavior="default" id="QvC-M9-y7g" customClass="MainFlutterWindow" customModule="Runner" customModuleProvider="target">
             <windowStyleMask key="styleMask" titled="YES" closable="YES" miniaturizable="YES" resizable="YES"/>
-            <rect key="contentRect" x="335" y="390" width="800" height="600"/>
+            <rect key="contentRect" x="335" y="390" width="350" height="600"/>
             <rect key="screenRect" x="0.0" y="0.0" width="2560" height="1577"/>
             <view key="contentView" wantsLayer="YES" id="EiT-Mj-1SZ">
-                <rect key="frame" x="0.0" y="0.0" width="800" height="600"/>
+                <rect key="frame" x="0.0" y="0.0" width="350" height="600"/>
                 <autoresizingMask key="autoresizingMask"/>
             </view>
         </window>